Must say I would also very interested to know. I demo'd the Westone UM3X today at our local distributor and I think they would make for very good rockers. I am not sure how the Westone 4 would compare in comparison to the UM3X as they didn't have a demo available on those. I have the Hifiman HE-500 and I'm looking for an IEM to complement these headphones.

I have the W4s and HD580s, so maybe I can try to answer this. I would put the W4s in between the HD600 and HD650 in terms of sound signature. Very similar, smooth, laid-back, slightly warm, inoffensive sound. Maybe closer to the HD650s though, what with the slight mid-bass emphasis. They are sort of in between in terms of upper-midrange and treble. They basically act as my HD580 substitute on the go, without losing any SQ (of course soundstage size is compromised, but positioning and imaging are still spot on). Rock sounds just as nice as on the HD580 as with the W4s.

I have the W4s and HD580s, so maybe I can try to answer this. I would put the W4s in between the HD600 and HD650 in terms of sound signature. Very similar, smooth, laid-back, slightly warm, inoffensive sound. Maybe closer to the HD650s though, what with the slight mid-bass emphasis. They are sort of in between in terms of upper-midrange and treble. They basically act as my HD580 substitute on the go, without losing any SQ (of course soundstage size is compromised, but positioning and imaging are still spot on). Rock sounds just as nice as on the HD580 as with the W4s.

Thank you very much for the response.

However out of curiosity, do you still use the HD 580 in conjunction with the 4s at home? Or do you just use the 580s.

The HD600 need AMPs help to show there best and IMO they are mid forward headphones and shows great detailed in mids, highs without toomuch bass. The IEMs i will recommend with simllar soundsignature are Sony EX1000, Phonak PFE232 and JVC FX700(bassier and not mid forward but very natural as HD600 and shows great details in all frequencies. The W4r are more balanced without emphesis on any frequency and overall great buy for balanced sound.

However out of curiosity, do you still use the HD 580 in conjunction with the 4s at home? Or do you just use the 580s.

Also when on the go, what do you listen to the 4s on? (Ex. iPhone 4s)

Thank you very much in advance.

I use my HD580s in combination with my other full-sized headphones at home. The W4s right now is the only thing I bring on the go. So I guess the W4s get more headtime.

I can either use an iTouch 2G, my phone, or a Clip+. They are very efficient, so any DAP will drive them plenty. I've tried other portable amps as well, and they get a little better. Although, I'd still drive them ampless as they don't improve enough to warrant the sacrifice in portability, IMO.

I think the general consensus (and from what I hear out of them everyday) is that the W4s are slightly midrange forward with a mild bump in the bass for some warmth. Not totally flat and neutral, but yes, mildly colored for that balanced, smooth sound.

Thanks for the interesting feedback, places the W4Rs well into perspective, though I would have expected some improvement in sound quality over the open HD600 and HD650 for the amount asked. But sounds like a very technically competent and balanced IEM which is very rare to find, so that makes up for the cost.

But if the W4 offers a sound signature somewhere in between the HD600 and HD650 I am definitely going to like them. Decided to place my order for 4R, will be receiving them sometime next week. Very excited!

Thanks for the interesting feedback, places the W4Rs well into perspective, though I would have expected some improvement in sound quality over the open HD600 and HD650 for the amount asked. But sounds like a very technically competent and balanced IEM which is very rare to find, so that makes up for the cost.

But if the W4 offers a sound signature somewhere in between the HD600 and HD650 I am definitely going to like them. Decided to place my order for 4R, will be receiving them sometime next week. Very excited!

Would love to hear your impressions, and it's comparison to the HE-500s! :)

@ Others, Thank you very much for your responses. It really helped me out!

I'd like to chime in and say I have the 4r and have compared it to the 580s. I was curious myself what the hd600 sounded like vs. the hd650 and 4r. I can tell you this, I was much more impressed with the 580 vs the 4r. The 4r is nowhere near as flat as the 580 in overall signature. This is backed up by graphs as well:

I find the 4r is the best I've heard in an iem, but requires EQ still. The hd580 doesn't. The 4r using accudio makes a much closer comparison but still falls short of the 580 a little in fullness.

I find the 4r to sound "flat" not in signature but in musicality. The highs are muffled (not really rolled off like the shure 535, but rather soft like you're under a pillow). The bass is decent, but the mid bass hump really masks a lot of details. Compared to other iems they do sound more neutral and high quality though, but just not really compared to true neutrality. I want to get a pair of senns because everyone i've heard has been excellent value-wise. The 439 were even pretty good at only $80. But I want something more capable.

Amazon has the 600 and 650 for the same price right now. I was wondering if anyone has the westone 4r and hd600/650? Could you download the free accudio iphone/ipod app and set the "simulation" mode to the hd600/650 series. I'm really curious how close the overall signature is to the real thing. I can already tell it still doesn't sound like over the ear headphones, but if the app is correct, the hd series sound like the EQ'd 4r out of the box. That would be perfect for me. They sound very very neutral. As the graph shows the 600/650 are very flat.

It looks like the 600 has slightly better treble and the 650 has more bass but less treble smoothness. If this is true, that is exactly what accudio sounds like when you switch between them. But I'm curious if the overall brightness/bassiness is the same in the real senns? If they are close to the 580s but flatter i think I'll like them a lot. The 580s have just the slightest V shape overall which is nice, but I'm looking for flat. :-)